Stainless steel bag filters are widely used in industries such as chemical, food, pharmaceutical, and water treatment due to their filtration accuracy, high flow rate, and durability. Standardized replacement, cleaning, and maintenance are crucial to ensure its long-term stable operation and extend its service life. This article will provide you with a fast, secure, and efficient maintenance tutorial.
1、 Core objective: Safety first, parallel efficiency
Before starting any operation, it is essential to comply with safety regulations:
1. Cut off power and pressure: Close the inlet and outlet valves of the filter, and open the exhaust valve to release all pressure inside the tank.
2. Wear protective equipment: Wear cut resistant gloves and goggles to prevent residual liquid splashing or sharp edge scratches.
3. Handling residual materials: For corrosive, toxic, or high-temperature materials, cleaning, neutralization, or cooling should be carried out to ensure safe operation.
2、 Four step method for quickly replacing filter bags
Step 1: Prepare and open the lid
Preparation tools: Prepare new filter bags of appropriate specifications, specialized opening wrenches (such as rocker arms), cleaning cloths, and containers for collecting waste liquids.
Opening operation: For the rocker arm quick opening structure, rotating the rocker arm counterclockwise can easily open the upper cover. For flange bolt connections, the nuts need to be loosened one by one in diagonal order. When opening the lid, the action should be slow. After confirming that there is no residual pressure inside, move the lid away.
Step 2: Remove the old filter bag
Remove the pressure ring/basket: Gently remove the pressure basket or pressure ring that secures the filter bag. Be careful not to shake off impurities from the filter bag onto the clean lower outlet.
Extracting filter bag: Carefully pinch the sealing mouth of the filter bag with your hand or tool, and lift it vertically upwards as a whole. Quickly place the removed old filter bags and impurities into the prepared waste container to prevent cross contamination.
Step 3: Clean and inspect the seals
Cleaning the filter chamber: Use a cleaning cloth or soft brush to clean the metal sealing surface, basket support seat, and inner wall inside the filter. Any residual particles may affect the sealing effect and service life of the new filter bag.
Check the sealing ring: Carefully inspect the O-ring on the upper cover for wear, aging, cracking, or deformation. If there is any damage, it must be replaced immediately, which is the key to ensuring that the filter operates without leakage.
Step 4: Install a new filter bag
Correct placement: Place the brand new and intact filter bag vertically inside the filter, ensuring that the sealing ring (or tightening ring) of the filter bag is flat and seated in the metal sealing groove.
Reset fasteners: Accurately place the pressure basket or pressure ring back and gently press it to ensure it is in place, firmly compressing the filter bag.
Close the lid: Align the lid with the position and cover it. For rocker arm type, tighten the rocker arm clockwise until significant resistance is felt to ensure proper sealing; For flange type, gradually tighten the nuts evenly in diagonal order to ensure even force distribution.
3、 Efficient Cleaning and Maintenance Guide
The cleaning of filter bags aims to achieve reuse and reduce costs (only applicable to washable filter bags).
1. Reverse flushing (method):
Flip the removed dirty filter bag over and rinse it with low-pressure water from the clean side (inner side) to the dirty side (outer side) of the filter bag. The direction of water flow is opposite to that of filtration, which can effectively wash away most of the particles embedded in the fibers.
2. Chemical immersion cleaning:
Prepare cleaning solution: Select the appropriate cleaning agent based on the nature of the impurities being filtered. For example, for oils and fats, a mild alkaline solution can be used; For scale or minerals, a weak acid solution (such as citric acid) can be used.
Soaking and rinsing: Soak the filter bag in the cleaning solution for 30 minutes to several hours (depending on the condition of the dirt). Afterwards, rinse the filter bag with a large amount of water until there is no residue of cleaning agent, and test it as neutral with pH test paper.
3. Natural drying and inspection:
Hang the cleaned filter bag in a ventilated and dust-free area to air dry naturally. Do not use hot air baking or direct sunlight to avoid damaging the fiber structure of the filter bag.
In a well lit area, carefully inspect the filter bag against the light for any damage, perforation, or cracking of the sealing ring. Any minor damage can cause filtration failure, and once discovered, it must be scrapped.
4、 Maintenance cycle and best practice recommendations
Differential pressure is a key indicator: the optimal time for replacement is when the pressure difference between the inlet and outlet of the filter reaches 0.1-0.2 MPa. Excessive pressure difference not only reduces flow rate, but may also crush the filter bag.
Establish maintenance records: Record the date of each replacement, pressure difference, filter material, and filter bag model, which helps analyze problems and predict maintenance cycles.
Spare parts management: Keep an appropriate amount of filter bags and sealing rings on hand for emergencies.